1. Field of the Invention
The present invention relates to lamellae for light deflection and for radiation scattering comprising a first portion, located in the area of irradiation E, including a step-shaped gradation of the lamella leaf consisting of a treadboard and a riser wherein the inclination .beta. of the treadboard forms an incline from the area of irradiation to the interior space, and a second portion.
2. Prior Art
From U.S. Pat. No. 2,103,788, it has been known to shape sun shade lamellae like steps and to arrange the lamellae horizontally. The disadvantage of such arrangement is that, both in summer and in winter, direct sun radiation is completely scattered. A further disadvantage is seen in that the lamellae are so tightly next to each other that transparency from within to the outside is not possible. An additional disadvantage is that only bottom radiation can penetrate between the lamellae into the interior space so that the interior space is not sufficiently illuminated.
It has furtheron been known to shape the lamellae for radiation screens as steps where the individual steps are arranged at different angles relative to each other and the treadboard and the riser are arranged in various lengths (German Offenlegungsschrift No. 27 32 592). From German Offenlegungsschrift No. 42 39 003 A1, too, sun shade lamellae have been known which are shaped as steps on the upper side and are disposed at right angles relative to each other. At the underside, the sun shade lamellae described are also shaped as steps. The individual steps on the underside of the lamella leaf are partly shaped concavely or convexly. The gradings on the upper side of the sun shade lamella are shaped level or plane. This causes reflection of the light radiation from the upper side of a lamella onto the underside of the upper lamella. On the underside of the upper lamella, the light radiation is then deflected by a corresponding concave shape so that controlled light deflection onto the working or ground area is obtained. Light deflection to the ceiling and into the depth of the room is only restrictedly possible. The double light deflection to the upper or the underside, respectively, of the sun shade lamellae is considered a disadvantage since each reflection, even on specular surfaces, leads to an absorption at the lamellae. The absorption leads to undesired heating up and reduction of the light radiation. If only the underside is arched and the upper side is plane or level, high angles of incidence of the sun in summer may lead to a plurality of reflections between the lamella leafs until the ray is reflected into the interior space or again to the outside. This leads to considerable warming up of the lamellae which, particularly in summer, is experienced as inconvenient heat radiation in the interior space. In case of a reflection movement between the lamellae, one cannot guarantee that light incidence is deflected to the ceiling and, in order to illuminate the depth of the room, into the interior depth. Glaring at the working place might even be experienced since no exact control over the angle of the light incidence into the interior space can be exerted.